Enantioselective Stetter reactions of enals and modified chalcones catalyzed by N-heterocyclic carbenes

New trick for an old cat.: Triazolium-based N-heterocyclic carbenes (NHCs) catalyze the selective generation of acyl anion equivalents for the title reaction. The stereoelectronic properties of the enal-derived Breslow intermediates and the unique reactivity of the modified chalcones are crucial for the Stetter reactions to occur. EWG=electron- withdrawing group